Liquid-crystalline medium and liquid-crystal display

ABSTRACT

The present invention relates to dielectrically positive liquid-crystalline media comprising a dielectrically positive component, component A, comprising a dielectrically positive compound of the formula (I), in which the parameters have the meaning indicated in the specification, and optionally a second dielectrically positive component, component B, comprising one or more dielectrically positive compounds having a dielectric anisotropy of greater than 3 and optionally a dielectrically neutral component, component C, and to liquid-crystal displays, especially to active-matrix displays and in particular to TN, IPS, FFS and OCB displays, containing these media.

FIELD OF THE INVENTION

The present invention relates to liquid-crystalline media and toliquid-crystal displays containing these media, especially to displaysaddressed by an active matrix and in particular to displays of thetwisted nematic (TN), in-plane switching (IPS) or fringe-field switching(FFS) type.

STATE OF THE ART AND PROBLEM TO BE SOLVED

Liquid-crystal displays (LCDs) are used in many areas for the display ofinformation. LCDs are used both for direct-view displays and forprojection-type displays. The electro-optical modes used are, forexample, the twisted nematic (TN), super twisted nematic (STN),optically compensated bend (OCB) and electrically controlledbirefringence (ECB) modes together with their various modifications, aswell as others. All these modes utilise an electric field which isessentially perpendicular to the substrates or the liquid-crystal layer.Besides these modes, there are also electro-optical modes that utilisean electric field which is essentially parallel to the substrates or theliquid-crystal layer, such as, for example, the in-plane switching (IPS)mode (as disclosed, for example, in DE 40 00 451 and EP 0 588 568) andthe fringe-field switching (FFS) mode, in which a strong “fringe field”is present, i.e. a strong electric field close to the edge of theelectrodes and, throughout the cell, an electric field which has both astrong vertical component and a strong horizontal component. Theselatter two electro-optical modes in particular are used for LCDs inmodern desktop monitors and are intended for use in displays for TV setsand multimedia applications. The liquid crystals in accordance with thepresent invention are preferably used in displays of this type. Ingeneral, dielectrically positive liquid-crystalline media having ratherlower values of the dielectric anisotropy are used in FFS displays, butin some cases liquid-crystalline media having a dielectric anisotropy ofonly about 3 or even less are also used in IPS displays.

For these displays, novel liquid-crystalline media having improvedproperties are required. The addressing times in particular have to beimproved for many types of application. Thus, liquid-crystalline mediahaving lower viscosities (η), especially having lower rotationalviscosities (γ₁), are required. The rotational viscosity should be 80mPa·s or less, preferably 60 mPa·s or less and especially 55 mPa·s orless. Besides this parameter, the media must have a nematic phase rangeof suitable width and position and an appropriate birefringence (Δn),and the dielectric anisotropy (Δε) should be sufficiently high to allowa reasonably low operating voltage. Δε should preferably be greater than3 and very preferably greater than 3, but preferably not greater than 21and in particular not greater than 19, as this would prevent an at leastfairly high resistivity.

The displays in accordance with the present invention are preferablyaddressed by an active matrix (active-matrix LCDs, AMDs for short),preferably by a matrix of thin-film transistors (TFTs). However, theliquid crystals according to the invention can also advantageously beused in displays having other known addressing means.

There are numerous different display modes which use composite systemsof low-molecular-weight liquid-crystal materials together with polymericmaterials. These are, for example, polymer dispersed liquid crystal(PDLC), nematic curvilinearly aligned phase (NCAP) and polymer network(PN) systems, as disclosed, for example, in WO 91/05 029, or axiallysymmetric microdomain (ASM) systems and others. In contrast to these,the modes that are especially preferred in accordance with the presentinvention use the liquid-crystal medium as such, oriented on surfaces.These surfaces are typically pretreated in order to achieve uniformalignment of the liquid-crystal material. The display modes inaccordance with the present invention preferably use an electric fieldwhich is substantially parallel to the composite layer.

Liquid-crystal compositions which are suitable for LCDs and especiallyfor IPS displays are known, for example, from JP 07-181 439 (A), EP 0667 555, EP 0 673 986, DE 195 09 410, DE 195 28 106, DE 195 28 107, WO96/23 851 and WO 96/28 521. However, these compositions have severedisadvantages. Amongst other deficiencies, most of them result indisadvantageously long addressing times, have inadequate values of theresistivity and/or require excessively high operating voltages.

Thus, there is a considerable need for liquid-crystalline media havingsuitable properties for practical applications, such as a broad nematicphase range, suitable optical anisotropy Δn corresponding to the displaytype used, a high Δε and particularly low viscosities.

PRESENT INVENTION

Surprisingly, it has now been found that it is possible to achieveliquid-crystalline media having a suitably high Δε, a suitable phaserange and Δn which do not exhibit the disadvantages of the materialsfrom the prior art, or at least only do so to a significantly lesserextent.

These improved liquid-crystalline media in accordance with the presentapplication comprise at least the following components:

-   -   a first dielectrically positive component, component A,        comprising one or more dielectrically positive compounds of the        formula I

in which

-   -   R¹ denotes alkyl, alkoxy, fluorinated alkyl or fluorinated        alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl        or fluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7        C atoms and preferably alkyl or alkenyl,    -   X¹ denotes —CN, halogen, halogenated alkyl or halogenated alkoxy        having 1 to 3 C atoms or halogenated alkenyl or halogenated        alkenyloxy having 2 or 3 C atoms, preferably F, Cl, —OCF₃, —CF₃        or —O—CH═CF₂, more preferably F, Cl or —OCF₃ and very preferably        F,    -   Y¹¹ and Y¹², independently of one another, denote H or F,        preferably Y¹¹ denotes F and particularly preferably Y¹¹ and Y¹²        both denote F, and    -   L¹¹ to L¹⁶, independently of one another, denote H or F,        preferably one, two or more denote F, particularly preferably        one, two or more of L¹¹, L¹³, L¹⁵ and L¹⁶ denote F, and very        particularly preferably L¹¹ to L¹³ and L¹⁵ all denote F, and    -   optionally a further dielectrically positive component,        component B, comprising one or more dielectrically positive        compounds, preferably having a dielectric anisotropy of greater        than 3, preferably selected from the group of the compounds of        the formulae II and III:

in which

-   -   R² and R³, independently of one another, denote alkyl, alkoxy,        fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms,        alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2        to 7 C atoms, and preferably R² and R³ denote alkyl or alkenyl,

-   -    independently of one another, denote

-   -   L²¹, L²², L³¹ and L³², independently of one another, denote H or        F, preferably L²¹ and/or L³¹ denote F,    -   X² and X³, independently of one another, denote halogen,        halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated        alkenyl or alkenyloxy having 2 or 3 C atoms, preferably F, Cl,        —OCF₃ or —CF₃, very preferably F, Cl or —OCF₃,    -   Z³ denotes —CH₂CH₂—, —CF₂CF₂—, —COO—, trans-CH═CH—,        trans-CF═CF—, —CH₂O— or a single bond, preferably —CH₂CH₂—,        —COO—, trans-CH═CH— or a single bond and very preferably —COO—,        trans-CH═CH— or a single bond, and    -   l, m, n and o, independently of one another, denote 0 or 1, and    -   optionally a dielectrically neutral component, component C,        comprising one or more dielectrically neutral compounds of the        formula IV

in which

-   -   R⁴¹ and R⁴², independently of one another, have the meaning        indicated above for R² under formula II, preferably R⁴¹ denotes        alkyl and R⁴² denotes alkyl or alkoxy or R⁴¹ denotes alkenyl and        R⁴² denotes alkyl,

-   -    independently of one another and, if

occurs twice, also these independently of one another, denote

-   -    preferably one or more of

-   -    denotes/denote

-   -   Z⁴¹ and Z⁴², independently of one another and, if Z⁴¹ occurs        twice, also these independently of one another, denote —CH₂CH₂—,        —COO—, trans-CH═CH—, trans-CF═CF—, —CH₂O—, —CF₂O—, —C≡C— or a        single bond, preferably one or more thereof denotes/denote a        single bond, and    -   p denotes 0, 1 or 2, preferably 0 or 1.

Component A preferably comprises, more preferably predominantly consistsof, even more preferably essentially consists of and very preferablycompletely consists of one or more dielectrically positive compounds ofthe formula I having a dielectric anisotropy of greater than 3 and inwhich the parameters have the respective meanings indicated above underformula I and X¹ preferably denotes F.

In a preferred embodiment of the present invention, component Acomprises, more preferably predominantly consists of, even morepreferably essentially consists of and very preferably completelyconsists of one or more dielectrically positive compounds having adielectric anisotropy of greater than 3, selected from the group of thecompounds of the formulae IA and IB:

in which the parameters have the meanings given above under formula I,and X¹ preferably denotes F, Cl, CF₃ or OCF₃, particularly preferably For Cl and very particularly preferably F.

In a preferred embodiment of the present invention, component Acomprises, more preferably predominantly consists of, even morepreferably essentially consists of and very preferably completelyconsists of one or more dielectrically positive compounds having adielectric anisotropy of greater than 3, selected from the group of thecompounds of the formulae IA-1 to IA-3:

in which the parameters have the respective meanings indicated aboveunder formula I or IA, and X¹ preferably denotes F, Cl, CF₃ or OCF₃,particularly preferably F or Cl and very particularly preferably F.

In a preferred embodiment of the present invention, component Acomprises, more preferably predominantly consists of, even morepreferably essentially consists of and very preferably completelyconsists of one or more dielectrically positive compounds having adielectric anisotropy of greater than 3, selected from the group of thecompounds of the formulae IB-1 and IB-2:

in which the parameters have the respective meanings indicated aboveunder formula I or IB, and X¹ preferably denotes F, Cl, CF₃ or OCF₃,particularly preferably F or Cl and very particularly preferably F.

The concentration of component A in the medium is preferably in therange from 1% to 25%, more preferably from 2% to 15%, even morepreferably from 2% to 10% and very preferably from 3% to 10%. If asingle homologous compound of the formula I is used in the medium, itsconcentration is preferably in the range from 1% to 10%; if two or morehomologous compounds of the formula I are used in the medium, 1% to 8%of the individual homologues are preferably used.

The media in accordance with the present invention preferably comprise afurther (for example second) dielectrically positive component,component B. This further dielectrically positive component, componentB, preferably comprises, more preferably predominantly consists of, evenmore preferably essentially consists of and very preferably completelyconsists of dielectrically positive compounds having a dielectricanisotropy of greater than 3.

This component, component B, preferably comprises, more preferablypredominantly consists of, even more preferably essentially consists ofand very preferably completely consists of one or more dielectricallypositive compounds having a dielectric anisotropy of greater than 3,selected from the group of the formulae II and III.

In a preferred embodiment of the present invention, component Bcomprises, more preferably predominantly consists of, even morepreferably essentially consists of and very preferably completelyconsists of one or more dielectrically positive compounds having adielectric anisotropy of greater than 3, selected from the group of thecompounds of the formulae II-1 to II-3:

in which the parameters have the respective meanings indicated aboveunder formula II, and in formula II-1 the parameters L²³ and L²⁴,independently of one another and of the other parameters, denote H or F,and in formula II-2,

independently of one another, preferably denote

Component B preferably comprises compounds selected from the group ofthe compounds of the formulae II-1 to II-3 in which L²¹ and L²² or L²³and L²⁴ both denote F.

In a preferred embodiment, component B comprises compounds selected fromthe group of the compounds of the formulae II-1 and II-2 in which L²¹,L²², L²³ and L²⁴ all denote F.

Component B preferably comprises one or more compounds of the formulaII-1. The compounds of the formula II-1 are preferably selected from thegroup of the compounds of the formulae II-1a to II-1j:

in which the parameters have the respective meanings indicated above,and L²⁵ to L²⁸, independently of one another, denote H or F, L²⁷ and L²⁸preferably both denote H, L²⁶ particularly preferably denotes H.

Component B preferably comprises compounds selected from the group ofthe compounds of the formulae II-1a to II-1e in which L²¹ and L²² bothdenote F and/or L²³ and L²⁴ both denote F.

In a preferred embodiment, component B comprises compounds selected fromthe group of the compounds of the formulae II-1a to II-1h in which L²¹,L²², L²³ and L²⁴ all denote F.

Especially preferred compounds of the formula II-1 are

in which R² and X² have the meanings indicated above, and X² preferablydenotes F.

Component B preferably comprises one or more compounds of the formulaII-2. The compounds of the formula II-2 are preferably selected from thegroup of the compounds of the formulae II-2a to II-2c:

in which the parameters have the respective meanings indicated above,and L²¹ and L²² preferably both denote F.

Component B preferably comprises one or more compounds of the formulaII-3. The compounds of the formula II-3 are preferably selected from thegroup of the compounds of the formulae II-3a to II-3e:

in which the parameters have the respective meanings indicated above,and L²⁵ and L²⁶, independently of one another and of the otherparameters, denote H or F, and preferably

in the formulae II-3a and II-3b

L²¹ and L²² both denote F,

in the formulae II-3c and II-3d

L²¹ and L²² both denote F and/or L²³ and L²⁴ both denote F, and

in formula II-3e

L²¹, L²² and L²³ denote F.

Especially preferred compounds of the formula II-3 are

in which R² has the meaning indicated above.

In a further preferred embodiment of the present invention, component Bcomprises, more preferably predominantly consists of, even morepreferably essentially consists of and very preferably completelyconsists of one or more dielectrically positive compounds having adielectric anisotropy of greater than 3, selected from the group of theformulae III-1 and III-2:

in which the parameters have the respective meanings indicated aboveunder formula III.

Component B preferably comprises one or more compounds of the formulaIII-1. The compounds of the formula III-1 are preferably selected fromthe group of the compounds of the formulae III-1a and III-1b:

in which the parameters have the respective meanings indicated above,and the parameters L³³ and L³⁴, independently of one another and of theother parameters, denote H or F.

Component B preferably comprises one or more compounds of the formulaIII-2. The compounds of the formula III-2 are preferably selected fromthe group of the compounds of the formulae III-2a to III-2h:

in which the parameters have the respective meanings indicated above,and the parameters L³⁵ and L³⁶, independently of one another and of theother parameters, denote H or F.

Component B preferably comprises one or more compounds of the formulaIII-1a, which are preferably selected from the group of the compounds ofthe formulae III-1a-1 to III-1a-6:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds of the formulaIII-1b, which are preferably selected from the group of the compounds ofthe formulae III-1b-1 to III-1b-4, preferably III-1b-4:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds of the formulaIII-2a, which are preferably selected from the group of the compounds ofthe formulae III-2a-1 to III-2a-5:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds of the formulaIII-2b, which are preferably selected from the group of the compounds ofthe formulae III-2b-1 and III-2b-2, preferably III-2b-2:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds of the formulaIII-2c, which are preferably selected from the group of the compounds ofthe formulae III-2c-1 to III-2c-5:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds selected from thegroup of the compounds of the formulae III-2d and III-2e, which arepreferably selected from the group of the compounds of the formulaeIII-2d-1 and III-2e-1:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds of the formulaIII-2f, which are preferably selected from the group of the compounds ofthe formulae III-2f-1 to III-2f-5:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds of the formulaIII-2g, which are preferably selected from the group of the compounds ofthe formulae III-2g-1 to III-2g-5:

in which R³ has the meaning indicated above.

Component B preferably comprises one or more compounds of the formulaIII-2h, which are preferably selected from the group of the compounds ofthe formulae III-2h-1 to III-2h-6:

in which R³ has the meaning indicated above.

Alternatively or in addition to the compounds of the formulae III-1and/or III-2, the media in accordance with the present invention maycomprise one or more compounds of the formula III-3

in which the parameters have the respective meanings indicated aboveunder formula III and are preferably selected from the group of theformulae III-3a and III-3b:

in which R³ has the meaning indicated above.

The liquid-crystalline media in accordance with the present inventionpreferably comprise a dielectrically neutral component, component C.This component has a dielectric anisotropy in the range from −1.5 to 3.It preferably comprises, more preferably predominantly consists of, evenmore preferably essentially consists of and especially preferablycompletely consists of dielectrically neutral compounds having adielectric anisotropy in the range from −1.5 to 3. This componentpreferably comprises, more preferably predominantly consists of, evenmore preferably essentially consists of and very preferably completelyconsists of one or more dielectrically neutral compounds having adielectric anisotropy in the range from −1.5 to 3, of the formula IV.

The dielectrically neutral component, component C, preferably comprisesone or more compounds selected from the group of the compounds of theformulae IV-1 to IV-6:

in which R⁴¹ and R⁴² have the respective meanings indicated above underformula IV, and in the formulae IV-1, IV-5 and IV-6 R⁴¹ preferablydenotes alkyl or alkenyl, preferably alkenyl, and R⁴² preferably denotesalkyl or alkenyl, preferably alkyl, in formula IV-2 R⁴¹ and R⁴²preferably denote alkyl, and in formula IV-4 R⁴¹ preferably denotesalkyl or alkenyl, more preferably alkyl, and R⁴² preferably denotesalkyl or alkoxy, more preferably alkoxy.

The dielectrically neutral component, component C, preferably comprisesone or more compounds selected from the group of the compounds of theformulae IV-1, IV-4, IV-5 and IV-6, preferably one or more compounds ofthe formula IV-1 and one or more compounds selected from the group ofthe formulae IV-4 and IV-5, more preferably in each case one or morecompounds of the formulae IV-1, IV-4 and IV-5 and very preferably ineach case one or more compounds of the formulae IV-1, IV-4, IV-5 andIV-6.

In a preferred embodiment, component C preferably comprises one or morecompounds of the formula IV-5, more preferably selected from therespective sub-formulae thereof of the formulae CCP-V-n and/or CCP-nV-mand/or CCP-Vn-m, more preferably of the formulae CCP-V-n and/or CCP-V2-nand very preferably selected from the group of the formulae CCP-V-1 andCCP-V2-1. The definitions of these abbreviations (acronyms) areindicated below in Table D or are evident from Tables A to C.

In a likewise preferred embodiment, component C preferably comprises oneor more compounds of the formula IV-1, more preferably selected from therespective sub-formulae thereof of the formulae CC-n-m, CC-n-V and/orCC-n-Vm, more preferably of the formulae CC-n-V and/or CC-n-Vm and verypreferably selected from the group of the formulae CC-3-V, CC-4-V,CC-5-V, CC-3-V1, CC-4-V1, CC-5-V1 and CC-3-V2. The definitions of theseabbreviations (acronyms) are likewise indicated below in Table D or areevident from Tables A to C.

In a further preferred embodiment of the present invention, which may bethe same as the above embodiment or a different embodiment, theliquid-crystal mixtures in accordance with the present inventioncomprise component C, which comprises, preferably predominantly consistsof and very preferably completely consists of compounds of the formulaIV selected from the group of the compounds of the formulae IV-1 to IV-6as indicated above and optionally of the formulae IV-7 to IV-13:

in which

-   -   R⁴¹ and R⁴², independently of one another, denote alkyl, alkoxy,        fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms,        alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2        to 7 C atoms, and    -   L⁴ denotes H or F.

In a preferred embodiment, component C preferably comprises one or morecompounds of the formula IV-7, more preferably selected from therespective sub-formulae thereof of the formulae CPP-3-2, CPP-5-2 andCGP-3-2, more preferably of the formulae CPP-3-2 and/or CGP-3-2 and veryparticularly preferably of the formula CPP-3-2. The definitions of theseabbreviations (acronyms) are indicated below in Table D or are evidentfrom Tables A to C.

Alternatively or in addition to the compounds of the formulae II and/orIII, the media in accordance with the present invention may comprise oneor more dielectrically positive compounds of the formula V

in which

-   -   R⁵ denotes alkyl, alkoxy, fluorinated alkyl or fluorinated        alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl        or fluorinated alkenyl having 2 to 7 C atoms and preferably        alkyl or alkenyl,

independently of one another, denote

-   -   L⁵¹ and L⁵², independently of one another, denote H or F,        preferably L⁵¹ denotes F, and    -   X⁵ denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C        atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C        atoms, preferably F, Cl, —OCF₃ or —CF₃, very preferably F, Cl or        —OCF₃,    -   Z⁵ denotes —CH₂CH₂—, —CF₂CF₂—, —COO—, trans-CH═CH—, trans-CF═CF—        or —CH₂O—, preferably —CH₂CH₂—, —COO— or trans-CH═CH— and very        preferably —COO— or trans-CH═CH—, and    -   q denotes 0 or 1.

The media in accordance with the present invention preferably compriseone or more compounds of the formula V, preferably selected from thegroup of the compounds of the formulae V-1 and V-2:

in which the parameters have the respective meanings indicated above,and the parameters L⁵³ and L⁵⁴, independently of one another and of theother parameters, denote H or F, and Z⁵ preferably denotes —CH₂—CH₂—.

The compounds of the formula V-1 are preferably selected from the groupof the compounds of the formulae V-1a and V-1b:

in which R⁵ has the meaning indicated above.

The compounds of the formula V-2 are preferably selected from the groupof the compounds of the formulae V-2a to V-2d:

in which R⁵ has the meaning indicated above.

The liquid-crystalline media in accordance with the present inventionpreferably comprise an additional dielectrically neutral component,component D. This component has a dielectric anisotropy in the rangefrom −1.5 to 3. It preferably comprises, more preferably predominantlyconsists of, even more preferably essentially consists of and especiallypreferably completely consists of dielectrically neutral compoundshaving a dielectric anisotropy in the range from −1.5 to 3. Thiscomponent preferably comprises, more preferably predominantly consistsof, even more preferably essentially consists of and very preferablycompletely consists of one or more dielectrically neutral compoundshaving a dielectric anisotropy in the range from −1.5 to 3, of theformula VI

in which

-   -   R⁶¹ and R⁶², independently of one another, have the meaning        indicated above for R² under formula II, preferably R⁶¹ denotes        alkyl and R⁶² denotes alkyl or alkenyl,

and, if it occurs twice, independently of one another on eachoccurrence, denotes

-   -    preferably one or more of

denotes/denote

-   -   Z⁶¹ and Z⁶², independently of one another and, if Z⁶¹ occurs        twice, also these independently of one another, denote —CH₂CH₂—,        —COO—, trans-CH═CH—, trans-CF═CF—, —CH₂O—, —CF₂O— or a single        bond, preferably one or more thereof denotes/denote a single        bond, and    -   r denotes 0, 1 or 2, preferably 0 or 1.

The dielectrically neutral component, component D, preferably comprisesone or more compounds selected from the group of the compounds of theformulae VI-1 and VI-2:

in which R⁶¹ and R⁶² have the respective meanings indicated above underformula VI, and R⁶¹ preferably denotes alkyl, and in formula VI-1 R⁶²preferably denotes alkenyl, preferably —(CH₂)₂—CH═CH—CH₃, and in formulaVI-2 R⁶² preferably denotes alkyl.

The dielectrically neutral component, component D, preferably comprisesone or more compounds selected from the group of the compounds of theformulae VI-1 and VI-2 in which R⁶¹ preferably denotes n-alkyl, and informula VI-1 R⁶² preferably denotes alkenyl, and in formula VI-2 R⁶²preferably denotes n-alkyl.

In a preferred embodiment, component D preferably comprises one or morecompounds of the formula VI-1, more preferably of the sub-formulaPP-n-2Vm thereof, even more preferably of the formula PP-1-2V1. Thedefinitions of these abbreviations (acronyms) are indicated below inTable D or are evident from Tables A to C.

In a preferred embodiment, component D preferably comprises one or morecompounds of the formula VI-2, more preferably of the sub-formulaPGP-n-m thereof, even more preferably of the sub-formula PGP-3-mthereof, very preferably selected from the formulae PGP-3-2, PGP-3-3,PGP-3-4 and PGP-3-5. The definitions of these abbreviations (acronyms)are likewise indicated below in Table D or are evident from Tables A toC.

Besides components A and B, the liquid-crystal mixtures in accordancewith the present invention preferably comprise at least one furthercomponent. This third component can be one of components C and D, thethird component present is preferably component C.

The mixtures in accordance with the present invention may of course alsocomprise all four components A, B, C and D and indeed do so in apreferred embodiment.

In addition, the liquid-crystal mixtures in accordance with the presentinvention may comprise a further optional component, component E, whichhas positive dielectric anisotropy and comprises, preferablypredominantly consists of, more preferably essentially consists of andvery preferably completely consists of dielectrically positivecompounds, preferably of the formula VII

in which

-   -   R⁷ has the meaning indicated above for R² under formula II,

one of

which is present denotes

preferably denotes

and the others have the same meaning or, independently of one another,denote

-   -    preferably

-   -   Z⁷¹ and Z⁷² independently of one another, denote —CH₂CH₂—,        —COO—, trans-CH═CH—, trans-CF═CF—, —CH₂O—, —CF₂O— or a single        bond, preferably one or more thereof denotes/denote a single        bond and very preferably both denote a single bond,    -   t denotes 0, 1 or 2, preferably 0 or 1, more preferably 1, and    -   X⁷ has the meaning indicated above for X² under formula II or        alternatively, independently of R⁸, can have the meaning        indicated for R⁸, and

wherefrom the compounds of the formula I are excluded.

The liquid-crystalline media in accordance with the present inventionpreferably comprise, more preferably predominantly consist of, even morepreferably essentially consist of and very preferably completely consistof components A to E, preferably A to D and very preferably A to C, andin particular compounds selected from the group of the compounds of theformulae I to VII, preferably I to V and very preferably I to III and/orIV.

In this application, comprise in connection with compositions means thatthe entity in question, i.e. the medium or the component, comprises thecomponent or components or compound or compounds indicated, preferablyin a total concentration of 10% or more and very preferably 20% or more.

In this connection, predominantly consist of means that the entity inquestion comprises 55% or more, preferably 60% or more and verypreferably 70% or more of the component or components or compound orcompounds indicated.

In this connection, essentially consist of means that the entity inquestion comprises 80% or more, preferably 90% or more and verypreferably 95% or more of the component or components or compound orcompounds indicated.

In this connection, completely consist of means that the entity inquestion comprises 98% or more, preferably 99% or more and verypreferably 100.0% of the component or components or compound orcompounds indicated.

Other mesogenic compounds which are not explicitly mentioned above mayalso optionally and advantageously be used in the media in accordancewith the present invention. Such compounds are known to the personskilled in the art.

The liquid-crystal media in accordance with the present inventionpreferably have a clearing point of 60° C. or more, particularlypreferably 70° C. or more and very particularly preferably 75° C. ormore.

The Δn of the liquid-crystal media in accordance with the presentinvention at 589 nm (Na^(D)) and 20° C. is preferably in the range from0.060 or more to 0.200 or less, more preferably in the range from 0.070or more to 0.180 or less, even more preferably in the range from 0.080or more to 0.170 or less and very preferably in the range from 0.100 ormore to 0.165 or less.

In a preferred embodiment of the present application, the Δn of theliquid-crystal media in accordance with the present invention ispreferably 0.080 or more, more preferably 0.090 or more.

The Δε of the liquid-crystal medium in accordance with the invention at1 kHz and 20° C. is preferably 2 or more, more preferably 4 or more andvery preferably 5 or more. In particular, Δε is 21 or less.

The nematic phase of the media according to the invention preferablyextends at least from 0° C. or less to 70° C. or more, more preferablyat least from −20° C. or less to 70° C. or more, very preferably atleast from −30° C. or less to 75° C. or more and in particular at leastfrom −40° C. or less to 75° C. or more.

In a first preferred embodiment of the present invention, the Δn of theliquid-crystal media is in the range from 0.120 or more to 0.150 orless, more preferably in the range from 0.125 or more to 0.145 or lessand very preferably in the range from 0.130 or more to 0.140 or less. Inthis embodiment, Δε is preferably in the range from 2 or more to 8 orless, particularly preferably in the range from 3 or more to 7 or lessand very particularly preferably in the range from 4 or more to 6 orless.

In this embodiment, the nematic phase of the media according to theinvention preferably extends at least from −20° C. or less to 70° C. ormore, more preferably at least from −20° C. or less to 70° C. or more,very preferably at least from −30° C. or less to 70° C. or more and inparticular at least from −40° C. or less to 70° C. or more.

In a second preferred embodiment of the present invention, the Δn of theliquid-crystal media is in the range from 0.110 or more to 0.140 orless, more preferably in the range from 0.115 or more to 0.135 or lessand very preferably in the range from 0.120 or more to 0.130 or less.

In this embodiment, Δε is preferably in the range from 6 or more to 12or less, particularly preferably in the range from 7 or more to 11 orless and very particularly preferably in the range from 8.0 or more to9.5 or less.

In this embodiment, the nematic phase of the media according to theinvention preferably extends at least from −20° C. or less to 70° C. ormore, more preferably at least from −20° C. or less to 70° C. or more,very preferably at least from −30° C. or less to 70° C. or more and inparticular at least from −40° C. or less to 70° C. or more.

In a third preferred embodiment of the present invention, the Δn of theliquid-crystal media is in the range from 0.090 or more to 0.130 orless, more preferably in the range from 0.100 or more to 0.120 or lessand very preferably in the range from 0.1080 or more to 0.1150 or less.

In this embodiment, Δε is preferably in the range from 12 or more to 19or less, particularly preferably in the range from 14 or more to 17 orless and very particularly preferably in the range from 15 or more to 16or less.

In this embodiment, the nematic phase of the media according to theinvention preferably extends at least from −20° C. or less to 75° C. ormore, more preferably at least from −30° C. or less to 70° C. or more,very preferably at least from −30° C. or less to 75° C. or more and inparticular at least from −30° C. or less to 80° C. or more.

In a fourth preferred embodiment of the present invention, the Δn of theliquid-crystal media is in the range from 0.140 or more to 0.180 orless, more preferably in the range from 0.150 or more to 0.170 or lessand very preferably in the range from 0.155 or more to 0.165 or less.

In this embodiment, Δε is preferably in the range from 11 or more to 18or less, particularly preferably in the range from 12 or more to 16 orless and very particularly preferably in the range from 13 or more to 15or less.

In this embodiment, the nematic phase of the media according to theinvention preferably extends at least from −20° C. or less to 80° C. ormore, more preferably at least from −30° C. or less to 80° C. or more,very preferably at least from −20° C. or less to 90° C. or more and inparticular at least from −20° C. or less to 100° C. or more.

In accordance with the present invention, component A is preferably usedin a concentration of 1% to 30%, more preferably 1% to 20%, even morepreferably 2% to 15% and very preferably 3% to 10% of the mixture as awhole.

Component B is preferably used in a concentration of 2% to 60%, morepreferably 3% to 55%, even more preferably 15% to 50% and verypreferably 20% to 45% of the mixture as a whole.

Component C is preferably used in a concentration of 0% to 70%, morepreferably 10% to 65%, even more preferably 20% to 60% and verypreferably 15% to 55% of the mixture as a whole.

Component D is preferably used in a concentration of 0% to 50%, morepreferably 1% to 40%, even more preferably 5% to 30% and very preferably10% to 20% of the mixture as a whole.

Component E is preferably used in a concentration of 0% to 30%, morepreferably 0% to 15% and very preferably 1% to 10% of the mixture as awhole.

The media according to the invention may optionally comprise furtherliquid-crystal compounds in order to adjust the physical properties.Such compounds are known to the person skilled in the art. Theirconcentration in the media in accordance with the present invention ispreferably 0% to 30%, more preferably 0.1% to 20% and very preferably 1%to 15%.

In the first preferred embodiment of the present invention, as mentionedabove, component A is preferably used in a concentration of 1% to 20%,more preferably 3% to 15% and very preferably 3% to 8% of the mixture asa whole, while component D is preferably used in a concentration of 1%to 30%, more preferably 5% to 25% and very preferably 5% to 20% of themixture as a whole.

In this preferred embodiment, the media preferably comprise one or morecompounds of the formula VI and very preferably of the formulae VI-1and/or VI-2.

Especially in the second preferred embodiment of the present invention,as mentioned above, component C preferably comprises one or morecompounds of the formula VI, more preferably of the formula VI-1, evenmore preferably selected from the respective sub-formulae thereof of theformulae CC-n-V and/or CC-n-Vm, more preferably of the formulae CC-n-V1and/or CC-n-V and very preferably selected from the group of theformulae CC-3-V, CC-4-V, CC-5-V and CC-3-V1. The definitions of theseabbreviations (acronyms) are indicated below in Table D.

Further preferred combinations of compounds and the concentrations andconcentration ranges in which these compounds are preferably employedarise for the person skilled in the art from the compositions given inthe Examples of the present application, in particular from Examples 9to 11 and 12.

The liquid-crystal media preferably comprise in total 50% to 100%, morepreferably 70% to 100% and very preferably 80% to 100% and in particular90% to 100% of components A, B, C and D, preferably components A, B andC, which in turn comprise, preferably predominantly consist of and verypreferably completely consist of one or more of the compounds of theformulae I, II, III, IV, V, VI and VII, preferably of the formulae I,II, III, IV, V and VI.

In the present application, the expression dielectrically positivedescribes compounds or components where Δε>3.0, dielectrically neutraldescribes those where −1.5≦Δε≦3.0 and dielectrically negative describesthose where Δε<−1.5. As is determined at a frequency of 1 kHz and at 20°C. The dielectric anisotropy of the respective compound is determinedfrom the results of a solution of 10% of the respective individualcompound in a nematic host mixture. If the solubility of the respectivecompound in the host mixture is less than 10%, the concentration isreduced to 5%. The capacitances of the test mixtures are determined bothin a cell having homeotropic alignment and in a cell having homogeneousalignment. The cell thickness of both types of cells is approximately 20μm. The voltage applied is a rectangular wave having a frequency of 1kHz and an effective value of typically 0.5 V to 1.0 V, but it is alwaysselected to be below the capacitive threshold of the respective testmixture.

Δε is defined as (ε∥−ε_(⊥)), while ε_(av.) is (ε∥+2ε_(⊥))/3.

The host mixture used for dielectrically positive compounds is mixtureZLI-4792 and that used for dielectrically neutral and dielectricallynegative compounds is mixture ZLI-3086, both from Merck KGaA, Germany.The absolute dielectric constants of the compounds are determined fromthe change in the respective values of the host mixture on addition ofthe compounds of interest. The values are extrapolated to aconcentration of the compounds of interest of 100%.

Components having a nematic phase at the measurement temperature of 20°C. are measured as such, all others are treated like compounds.

The expression threshold voltage in the present application refers tothe optical threshold and is quoted for 10% relative contrast (V₁₀), andthe expression saturation voltage refers to the optical saturation andis quoted for 90% relative contrast (V₉₀), in both cases unlessexpressly stated otherwise. The capacitive threshold voltage (V₀), alsocalled the Freedericks threshold (V_(Fr)), is only used if expresslymentioned.

The ranges of the parameters indicated in this application all includethe limit values, unless expressly stated otherwise.

The different upper and lower limit values indicated for various rangesof properties in combination with one another give rise to additionalpreferred ranges.

Throughout this application, the following conditions and definitionsapply, unless expressly stated otherwise. All concentrations are quotedin per cent by weight and relate to the respective mixture as a whole,all temperatures are quoted in degrees Celsius and all temperaturedifferences are quoted in differential degrees. All physical propertiesare determined in accordance with “Merck Liquid Crystals, PhysicalProperties of Liquid Crystals”, Status November 1997, Merck KGaA,Germany, and are quoted for a temperature of 20° C., unless expresslystated otherwise. The optical anisotropy (Δn) is determined at awavelength of 589.3 nm. The dielectric anisotropy (Δε) is determined ata frequency of 1 kHz. The threshold voltages, as well as all otherelectro-optical properties, are determined using test cells produced atMerck KGaA, Germany. The test cells for the determination of Δε have acell thickness of approximately 20 μm. The electrode is a circular ITOelectrode having an area of 1.13 cm² and a guard ring. The orientationlayers are SE-1211 from Nissan Chemicals, Japan, for homeotropicorientation (ε∥) and polyimide AL-1054 from Japan Synthetic Rubber,Japan, for homogeneous orientation (ε_(⊥)). The capacitances aredetermined using a Solatron 1260 frequency response analyser using asine wave with a voltage of 0.3 V_(rms). The light used in theelectro-optical measurements is white light. A set-up using acommercially available DSM instrument from Autronic-Melchers, Germany,is used here. The characteristic voltages have been determined underperpendicular observation. The threshold (V₁₀), mid-grey (V₅₀) andsaturation (V₉₀) voltages have been determined for 10%, 50% and 90%relative contrast respectively.

The liquid-crystal media in accordance with the present invention maycomprise further additives and chiral dopants in the usualconcentrations. The total concentration of these further constituents isin the range from 0% to 10%, preferably 0.1% to 6%, based on the mixtureas a whole. The concentrations of the individual compounds used are eachpreferably in the range from 0.1% to 3%. The concentration of these andsimilar additives is not taken into consideration when quoting thevalues and concentration ranges of the liquid-crystal components andliquid-crystal compounds of the liquid-crystal media in thisapplication.

The liquid-crystal media according to the invention consist of aplurality of compounds, preferably 3 to 30, more preferably 4 to 20 andvery preferably 4 to 16 compounds. These compounds are mixed in aconventional manner. In general, the desired amount of the compound usedin the smaller amount is dissolved in the compound used in the largeramount. If the temperature is above the clearing point of the compoundused in the higher concentration, it is particularly easy to observecompletion of the dissolution process. It is, however, also possible toprepare the media in other conventional ways, for example usingso-called pre-mixes, which can be, for example, homologous or eutecticmixtures of compounds, or using so-called “multibottle” systems, theconstituents of which are themselves ready-to-use mixtures.

By addition of suitable additives, the liquid-crystal media inaccordance with the present invention can be modified in such a way thatthey can be used in all known types of liquid-crystal displays, eitherusing the liquid-crystal media as such, such as TN, TN-AMD, ECB-AMD,VAN-AMD, IPS-AMD, FFS-AMD and OCB-AMD LCDs, or in composite systems,such as PDLC, NCAP, PN LCDs and especially in ASM-PA LCDs.

All temperatures, such as, for example, the melting point T(C,N) orT(C,S), the transition from the smectic (S) to the nematic (N) phaseT(S,N) and the clearing point T(N,I) of the liquid crystals, are quotedin degrees Celsius. All temperature differences are quoted indifferential degrees.

In the present invention and especially in the following examples, thestructures of the mesogenic compounds are indicated by means ofabbreviations, also called acronyms. In these acronyms, the chemicalformulae are abbreviated as follows using Tables A to C below. Allgroups C_(n)H_(2n+1), C_(m)H_(2m+1) and C_(l)H_(2l+1) or C_(n)H_(2n−1),C_(m)H_(2m−1) and C_(l)H_(2l−1) denote straight-chain alkyl or alkenyl,preferably 1E-alkenyl, each having n, m and l C atoms respectively.Table A lists the codes used for the ring elements of the corestructures of the compounds, while Table B shows the linking groups.Table C gives the meanings of the codes for the left-hand or right-handend groups. Table D shows illustrative structures of compounds togetherwith their respective abbreviations.

TABLE A Ring elements C

D

DI

A

AI

P

G

GI

U

UI

Y

M

MI

N

NI

Np

N3f

N3fI

tH

tHI

tH2f

tH2fI

dH

K

KI

nC

nCI

L

LI

F

FI

TABLE B Linking groups E —CH₂CH₂— Z —CO—O— V —CH═CH— ZI —O—CO— X —CF═CH—O —CH₂—O— XI —CH═CF— OI —O—CH₂— B —CF═CF— Q —CF₂—O— T —C≡C— QI —O—CF₂— W—CF₂CF₂— T —C≡C—

TABLE C End groups Left-hand side Right-hand side Use alone -n-C_(n)H_(2n+1)— -n —C_(n)H_(2n+1) -nO- C_(n)H_(2n+1)—O— -nO—O—C_(n)H_(2n+1) -V- CH₂═CH— -V —CH═CH₂ -nV- C_(n)H_(2n+1)—CH═CH— -nV—C_(n)H_(2n)—CH═CH₂ -Vn- CH₂═CH—C_(n)H_(2n+1)— -Vn —CH═CH—C_(n)H_(2n+1)-nVm- C_(n)H_(2n+1)—CH═CH—C_(m)H_(2m)— -nVm—C_(n)H_(2n)—CH═CH—C_(m)H_(2m+1) -N- N≡C— -N —C≡N -S- S═C═N— -S —N═C═S-F- F— -F —F -CL- Cl— -CL —Cl -M- CFH₂— -M —CFH₂ -D- CF₂H— -D —CF₂H -T-CF₃— -T —CF₃ -MO- CFH₂O— -OM —OCFH₂ -DO- CF₂HO— -OD —OCF₂H -TO- CF₃O—-OT —OCF₃ -OXF- CF₂═CH—O— -OXF —O—CH═CF₂ -A- H—C≡C— -A —C≡C—H -nA-C_(n)H_(2n+1)—C≡C— -An —C≡C—C_(n)H_(2n+1) -NA- N≡C—C≡C— -AN —C≡C—C≡N Usetogether - . . . A . . . - —C≡C— - . . . A . . . —C≡C— - . . . V . . . -CH═CH— - . . . V . . . —CH═CH— - . . . Z . . . - —CO—O— - . . . Z . . .—CO—O— - . . . ZI . . . - —O—CO— - . . . ZI . . . —O—CO— - . . . K . .. - —CO— - . . . K . . . —CO— - . . . W . . . - —CF═CF— - . . . W . . .—CF═CF—

in which n and m each denote integers, and the three dots “ . . . ” areplaceholders for other abbreviations from this table.

The following table shows illustrative structures together with theirrespective abbreviations. These are shown in order to illustrate themeaning of the rules for the abbreviations. They furthermore representcompounds which are preferably used.

TABLE D Illustrative structures

CC-n-m

CC-n-Om

CC-n-V

CC-n-Vm

CC-n-mV

CC-n-mVI

CC-V-V

CC-V-mV

CC-V-Vm

CC-Vn-mV

CC-nV-mV

CC-nV-Vm

CP-n-m

CP-nO-m

CP-n-Om

PP-n-m

PP-nO-m

PP-n-Om

PP-n-V

PP-n-Vm

PP-n-mV

PP-n-mVI

CCP-n-m

CCP-nO-m

CCP-n-Om

CCP-n-V

CCP-n-Vm

CCP-n-mV

CCP-n-mVI

CCP-V-m

CCP-nV-m

CCP-Vn-m

CCP-nVm-I

CPP-n-m

CPG-n-m

CGP-n-m

CPP-nO-m

CPP-n-Om

CPP-V-m

CPP-nV-m

CPP-Vn-m

CPP-nVm-I

PGP-n-m

CPPC-n-m

CGPC-n-m

CCPC-n-m

CCZPC-n-m

CPGP-n-m

PGIGP-n-m

CP-n-CL

CP-n-F

CCP-n-OT

CCG-n-OT

CCP-n-CL

CCP-n-F

CCG-n-F

CCG-V-F

CCG-V-F

CCU-n-F

CDU-n-F

CPP-n-F

CPG-n-F

CPU-n-F

CGU-n-F

PGU-n-F

CCGU-n-F

CPGU-n-F

GGP-n-F

GGP-n-CL

PGIGI-n-F

PGIGI-n-CL

CPGU-n-OT

PPGU-n-F

CCQP-n-F

CCQP-n-F

CCQG-n-F

CCQU-n-F

PUQU-n-F

CDUQU-n-F

CPUQU-n-F

CGUQU-n-F

PGUQU-n-F

APUQU-n-F

DPUQU-n-F

ADUQU-n-F

DAUQU-n-F

CLUQU-n-F

ALUQU-n-F

DUQU-n-F

LGPQU-n-F

PPGGQU-n-F

PGGGQU-n-F

PGPUQU-n-F

PGGUQU-n-F

The following table, Table E, shows illustrative compounds which can beused as stabiliser in the mesogenic media in accordance with the presentinvention.

TABLE E

In a preferred embodiment of the present invention, the mesogenic mediacomprise one or more compounds selected from the group of the compoundsfrom Table E.

The following table, Table F, shows illustrative compounds which canpreferably be used as chiral dopants in the mesogenic media inaccordance with the present invention.

TABLE F

C 15

CB 15

CM 21

CM 44

CM 45

CM 47

CC

CN

R/S-811

R/S-1011

R/S- 2011

R/S-3011

R/S-4011

R/S-5011

In a preferred embodiment of the present invention, the mesogenic mediacomprise one or more compounds selected from the group of the compoundsfrom Table F.

The mesogenic media in accordance with the present applicationpreferably comprise two or more, preferably four or more, compoundsselected from the group consisting of the compounds from the abovetables.

The liquid-crystal media in accordance with the present inventionpreferably comprise

-   -   seven or more, preferably eight or more, compounds, preferably        compounds having three or more, preferably four or more,        different formulae, selected from the group of the compounds        from Table D.

EXAMPLES

The examples below illustrate the present invention without limiting itin any way.

However, the physical properties show the person skilled in the art whatproperties can be achieved and in what ranges they can be modified. Inparticular, the combination of the various properties which canpreferably be achieved is thus well defined for the person skilled inthe art.

Example 1

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGPUQU-3-F 3.0 2 PGU-3-F 9.0 3PUQU-3-F 5.0 4 PGUQU-3-F 5.0 5 CC-3-V 36.0 6 CC-3-V1 7.0 7 PP-1-2V1 7.08 CCP-V-1 9.0 9 PGP-2-3 6.0 10  PGP-2-4 6.0 11  PGP-2-5 7.0 Σ 100.0Physical properties T(N, I) = 74° C. Δn (20° C., 589.3 nm) = 0.1348ε_(||) (20° C., 1 kHz) = 8.0 Δε (20° C., 1 kHz) = 5.0 γ₁ (20° C.) = 59mPa · s V₁₀ (20° C.) = 1.94 V V₉₀ (20° C.) = 2.85 V

This mixture is very highly suitable for displays in TN mode and inparticular for displays for use as monitor for a PC.

Example 2

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU-3-F 3.0 2 PGU-3-F 9.5 3PUQU-3-F 5.0 4 PGUQU-3-F 4.5 5 CC-3-V 36.5 6 CC-3-V1 7.0 7 PP-1-2V1 7.08 CCP-V-1 8.5 9 PGP-2-3 6.0 10  PGP-2-4 6.0 11  PGP-2-5 7.0 Σ 100.0Physical properties T(N, I) = 73° C. Δn (20° C., 589.3 nm) = 0.1340ε_(||) (20° C., 1 kHz) = 8.1 Δε (20° C., 1 kHz) = 5.1 γ₁ (20° C.) = 58mPa · s V₁₀ (20° C.) = 1.90 V V₉₀ (20° C.) = 2.81 V

This mixture is very highly suitable for displays in TN mode and inparticular for displays for use as monitor for a PC.

Example 3

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU-3-F 3.0 2 PGU-3-F 10.0 3PUQU-3-F 13.0 4 PGUQU-3-F 8.0 5 CC-3-V 34.0 6 CC-3-V1 7.0 7 CCP-V-1 15.08 PGP-2-3 3.0 9 PGP-2-4 4.0 10  PGP-2-5 3.0 Σ 100.0 Physical propertiesT(N, I) = 74° C. Δn (20° C., 589.3 nm) = 0.1238 ε_(||) (20° C., 1 kHz) =11.9 Δε (20° C., 1 kHz) = 8.6 γ₁ (20° C.) = 65 mPa · s V₁₀ (20° C.) =1.45 V V₉₀ (20° C.) = 2.20V V

This mixture is very highly suitable for displays in TN mode and inparticular for displays for use as monitor in a notebook (with 4 Vdriver).

Example 4

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU-3-F 3.5 2 PGU-3-F 11.0 3PUQU-3-F 12.0 4 PGUQU-3-F 8.5 5 CC-3-V 34.0 6 CC-3-V1 7.0 7 CCP-V-1 14.08 PGP-2-3 3.0 9 PGP-2-4 4.0 10  PGP-2-5 3.0 Σ 100.0 Physical propertiesT(N, I) = 74.5° C. Δn (20° C., 589.3 nm) = 0.1260 ε_(||) (20° C., 1 kHz)= 12.3 Δε (20° C., 1 kHz) = 8.9 γ₁ (20° C.) = 66 mPa · s V₁₀ (20° C.) =1.41 V V₉₀ (20° C.) = 2.16 V

This mixture is very highly suitable for displays in TN mode and inparticular for displays for use as monitor in a notebook (with 4 Vdriver).

Example 5

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU-3-F 4.0 2 CCU-3-F 8.0 3CCQU-2-F 10.0 4 CCQU-3-F 14.0 5 PUQU-3-F 15.0 6 APUQU-3-F 12.0 7PGUQU-3-F 3.0 8 CC-3-V 18.0 9 CC-3-V1 6.0 10  CCP-V-1 10.0 Σ 100.0Physical properties T(N, I) = 80° C. Δn (20° C., 589.3 nm) = 0.1016ε_(||) (20° C., 1 kHz) = 19.7 γ₁ (20° C.) = 105 mPa · s V₁₀ (20° C.) =1.08 V V₉₀ (20° C.) = 1.73 V

This mixture is very highly suitable for displays in TN mode and inparticular for displays for use as monitor in a notebook (with 2.5 Vdriver).

Example 6

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGPUQU-3-F 3.0 2 PGPUQU-4-F 3.02 CP-3-CL 3.0 3 CPP-2-F 3.0 4 CPP-3-F 3.0 5 CPG-2-F 6.0 6 CPG-3-F 7.0 7PGU-2-F 7.0 8 PGU-3-F 6.0 9 PUQU-2-F 6.0 10  PUQU-3-F 11.0 11  APUQU-3-F6.0 12  CC-4-V 18.0 13  CPGP-4-3 6.0 14  CPGP-5-2 6.0 15  CPGP-5-3 6.0 Σ100.0 Physical properties T(N, I) = 101° C. n_(e) (20° C., 589.3 nm) =1.6624 Δn (20° C., 589.3 nm) = 0.1603 ε_(||) (20° C., 1 kHz) = 18.4 Δε(20° C., 1 kHz) = 14.8 k₁ (20° C.) = 12.4 pN k₃/k₁ (20° C.) = 1.03 V₀(20° C.) = 0.99 V

This mixture is very highly suitable for displays in OCB mode and inparticular for displays having a broad working-temperature range.

Example 7

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGPUQU-4-F 3.0 2 CP-3-CL 3.0 2CPP-2-F 3.0 3 CPP-3-F 3.0 4 CPG-2-F 5.0 5 CPG-3-F 6.0 6 PGU-2-F 7.0 7PGU-3-F 6.0 8 PPGU-3-F 2.0 9 PUQU-2-F 6.0 10  PUQU-3-F 12.0 11 APUQU-3-F 7.0 12  CC-4-V 18.0 13  CPGP-4-3 7.0 14  CPGP-5-2 6.0 15 CPGP-5-3 6.0 Σ 100.0 Physical properties T(N, I) = 101° C. n_(e) (20°C., 589.3 nm) = 1.6629 Δn (20° C., 589.3 nm) = 0.1611 ε_(||) (20° C., 1kHz) = 18.3 Δε (20° C., 1 kHz) = 14.1 k₁ (20° C.) = 13.2 pN k₃/k₁ (20°C.) = 0.92 V₀ (20° C.) = 1.02 V

This mixture is very highly suitable for displays in OCB mode and inparticular for displays having a broad working-temperature range, suchas, for example, for mobile navigation systems, in particular, forexample, car navigation systems (CNSs).

Example 8

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGPUQU-4-F 3.0 2 CP-3-CL 4.0 2CPP-2-F 4.0 3 CPP-3-F 4.0 4 CPG-2-F 5.0 5 CPG-3-F 5.0 6 PGU-2-F 8.0 7PPGU-3-F 2.0 8 PUQU-2-F 6.0 9 PUQU-3-F 17.0 10  APUQU-3-F 6.0 11  CC-4-V16.0 12  CPGP-4-3 8.0 13  CPGP-5-2 12.0 Σ 100.0 Physical properties T(N,I) = 100° C. n_(e) (20° C., 589.3 nm) = 1.6622 Δn (20° C., 589.3 nm) =0.1601 ε_(||) (20° C., 1 kHz) = 18.2 Δε (20° C., 1 kHz) = 14.0 γ₁ (20°C.) = 158 mPa · s k₁ (20° C.) = 12.7 pN k₃/k₁ (20° C.) = 0.94 V₀ (20°C.) = 1.00 V

This mixture is very highly suitable for displays in OCB mode and inparticular for displays having a broad working-temperature range, forexample for CNSs.

Example 9

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU-5-F 7.0 2 CP-3-CL 5.0 2GGP-2-F 3.0 3 GGP-3-F 3.0 4 PGU-2-F 6.0 5 PGU-3-F 8.0 6 PGU-5-F 8.0 7PUQU-2-F 8.0 8 PUQU-3-F 14.0 9 CCGU-3-F 3.0 10  CC-3-V1 7.0 11  CCP-V-114.0 12  CCP-V2-1 8.0 13  CGPC-3-3 3.0 14  CGPC-5-3 3.0 Σ 100.0 Physicalproperties T(N, I) = 91.5° C. n_(e) (20° C., 589.3 nm) = 1.6603 Δn (20°C., 589.3 nm) = 0.1579 ε_(||) (20° C., 1 kHz) = 22.5 Δε (20° C., 1 kHz)= 18.1 γ₁ (20° C.) = 173 mPa · s k₁ (20° C.) = 12.2 pN k₃/k₁ (20° C.) =1.25 V₀ (20° C.) = 0.87 V

This mixture is very highly suitable for displays in OCB mode and inparticular for displays, for example for CNSs.

Example 10

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU-6-F 7.0 2 CP-3-CL 5.0 2GGP-2-F 3.0 3 GGP-3-F 3.0 4 PGU-2-F 6.0 5 PGU-3-F 8.0 6 PGU-5-F 8.0 7PUQU-2-F 8.0 8 PUQU-3-F 14.0 9 CCGU-3-F 3.0 10  CC-3-V1 7.0 11  CCP-V-114.0 12  CCP-V2-1 8.0 13  CGPC-3-3 3.0 14  CGPC-5-3 3.0 Σ 100.0 Physicalproperties T(N, I) = 91.5° C. n_(e) (20° C., 589.3 nm) = 1.6601 Δn (20°C., 589.3 nm) = 0.1575 ε_(||) (20° C., 1 kHz) = 22.5 Δε (20° C., 1 kHz)= 18.0 γ₁ (20° C.) = 174 mPa · s k₁ (20° C.) = 12.1 pN k₃/k₁ (20° C.) =1.25 V₀ (20° C.) = 0.87 V

This mixture is very highly suitable for displays in OCB mode and inparticular for displays, for example for CNSs.

Example 11

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU5-F 3.0 2 PGGUQU-6-F 4.0 2CP-3-CL 5.0 3 GGP-2-F 3.0 4 GGP-3-F 3.0 5 PGU-2-F 6.0 6 PGU-3-F 8.0 7PGU-5-F 8.0 8 PUQU-2-F 8.0 9 PUQU-3-F 14.0 10  CCGU-3-F 3.0 11  CC-3-V17.0 12  CCP-V-1 14.0 13  CCP-V2-1 8.0 14  CGPC-3-3 3.0 15  CGPC-5-3 3.0Σ 100.0 Physical properties T(N, I) = 91.5° C. n_(e) (20° C., 589.3 nm)= 1.1602 Δn (20° C., 589.3 nm) = 0.1577 ε_(||) (20° C., 1 kHz) = 22.5 Δε(20° C., 1 kHz) = 18.1 γ₁ (20° C.) = 174 mPa · s k₁ (20° C.) = 12.2 pNk₃/k₁ (20° C.) = 1.25 V₀ (20° C.) = 0.87 V

This mixture is very highly suitable for displays in OCB mode and inparticular for displays, for example for CNSs.

Example 12

A liquid-crystal mixture having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PGGUQU-5-F 6.0 2 PGGUQU-6-F 4.02 CPG-2-F 10.0 3 CPG-3-F 10.0 4 CPG-5-F 10.0 5 CPU-5-F 18.0 6 PGIGI-3-F7.0 7 PGU-2-F 2.0 8 PGU-3-F 10.0 9 PGU-5-F 10.0 10  CCGU-3-F 5.0 11 CGPC-3-3 3.0 12  CGPC-5-3 3.0 13  CGPC-5-5 2.0 Σ 100.0 Physicalproperties T(N, I) = 105.5° C. n_(e) (20° C., 589.3 nm) = 1.6882 Δn (20°C., 589.3 nm) = 0.1786 ε_(||) (20° C., 1 kHz) = 20.3 Δε (20° C., 1 kHz)= 15.6 γ₁ (20° C.) = n.d. mPa · s k₁ (20° C.) = 11.1 pN k₃/k₁ (20° C.) =1.33 V₀ (20° C.) = n.d. V

Note: n.d.: not determined

This mixture is very highly suitable for displays in OCB mode and inparticular for displays, for example for CNSs.

1. Liquid-crystal medium, characterised in that it comprises thefollowing: a first dielectrically positive component, component A,comprising one or more dielectrically positive compounds of the formulaI

in which R¹ denotes alkyl, alkoxy, fluorinated alkyl or fluorinatedalkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl orfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms, X¹denotes —CN, halogen, halogenated alkyl or halogenated alkoxy having 1to 3 C atoms or halogenated alkenyl or halogenated alkenyloxy having 2or 3 C atoms, Y¹ denotes ═N—, ═(CH)— or ═(CF)—, Y¹¹ and Y¹²,independently of one another, denote H or F, and L¹¹ to L¹⁶,independently of one another, denote H or F, and optionally a further(for example second) dielectrically positive component, component B,comprising one or more dielectrically positive compounds, preferablyselected from the group of the compounds of the formulae II and III:

in which R² and R³, independently of one another, denote alkyl, alkoxy,fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl,alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms,

 independently of one another, denote

L²¹, L²², L³¹ and L³², independently of one another, denote H or F, X²and X³, independently of one another, denote halogen, halogenated alkylor alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxyhaving 2 or 3 C atoms, Z³ denotes —CH₂CH₂—, —CF₂CF₂—, —COO—,trans-CH═CH—, trans-CF═CF—, —CH₂O— or a single bond, and l, m, n and o,independently of one another, denote 0 or 1, and optionally adielectrically neutral component, component C, comprising one or moredielectrically neutral compounds of the formula IV

in which R⁴¹ and R⁴², independently of one another, have the meaningindicated above for R² under formula II,

 independently of one another and, if

 occurs twice, also these independently of one another, denote

Z⁴¹ and Z⁴², independently of one another and, if Z⁴¹ occurs twice, alsothese independently of one another, denote —CH₂CH₂—, —COO—,trans-CH═CH—, trans-CF═CF—, —CH₂O—, —CF₂O—, —C≡C— or a single bond, andp denotes 0, 1 or
 2. 2. Liquid-crystal medium according to claim 1,characterised in that the concentration of component A in the medium isin the range from 1% to 30%.
 3. Liquid-crystal medium according to claim1, characterised in that component A comprises one or more compounds ofthe formula I in which X¹ denotes F.
 4. Liquid-crystal medium accordingto claim 1, characterised in that it comprises one or more compounds ofthe formula II.
 5. Liquid-crystal medium according to claim 1,characterised in that it comprises one or more compounds of the formulaIII.
 6. Liquid-crystal medium according to claim 1, characterised inthat it comprises one or more dielectrically neutral compounds of theformula IV.
 7. Liquid-crystal medium according to claim 1, characterisedin that it comprises a dielectrically neutral component, component D,comprising one or more dielectrically neutral compounds of the formulaVI

in which R⁶¹ and R⁶², independently of one another, have the meaningindicated for R²,

and, if it occurs twice, independently of one another on eachoccurrence, denotes

Z⁶¹ and Z⁶², independently of one another and, if Z⁶¹ occurs twice, alsothese independently of one another, denote —CH₂CH₂—, —COO—,trans-CH═CH—, trans-CF═CF—, —CH₂O—, —CF₂O— or a single bond, and rdenotes 0, 1 or
 2. 8. Liquid-crystal display, characterised in that itcontains a liquid-crystal medium according to claim
 1. 9. Liquid-crystaldisplay according to claim 8, characterised in that it is addressed byan active matrix.
 10. A method of using a liquid-crystal mediumaccording to claim 1 in a liquid-crystal display.